Reality check: Are those weight-loss shakes you've been drinking ineffective?

Drinking weight-loss shakes may not be benefiting you in your weight-loss journey, a new study by the European Association for the Study of Obesity says.

According to researchers, nearly 80 per cent of commercially sold weight-loss shakes in the U.K. were found to be labelled with unsubstantiated health claims – claims researchers say are exaggerated or untrue.

To find this out, Dr. Kelly Johnston and her team from LighterLife and Kings College London analyzed all commercially available “meal replaces for weight control” shakes sold in the U.K. in 2017. They measured the nutrient composition, legal compliance and consumer understanding of health and nutrition claims on the packages of the shakes.

That’s when they found that only 10 of the brands provided enough information as per the EU compositional and labelling requirements. The majority, however, did not meet even the basic compositional criteria needed to be called a “meal replacement for weight control,” the study says.

The team also found that 90 per cent of the tested products made at least one nutritional claim and just over half made at least one health claim. However, 79 per cent of these claims were not compliant with regulations.

But that’s not to say all meal replacements for weight control products don’t work. In fact, the team acknowledges that they can be an effective weight management tool if the products meet regulations.

So what is the deal with weight-loss shakes? Is this something Canadian dietitians recommend, or should consumers beware of these products?

For registered dietitian Desiree Nielsen, the results of the U.K. study don’t surprise her. And while the results only focus on the U.K., Nielsen says it’s still important for Canadians to be aware because, despite the inspection-based system in Canada, products with unauthorized claims can still make it to market.

“In Canada, we have many products on the market claiming to be beneficial for weight loss, not just shakes,” she says. “These products are marketed with the full knowledge of the consumer that they are targeting and will use health and nutrition claims such as gluten-free or low fat to encourage purchase.”

But what about meal replacement shakes in general — do they actually work?

“Traditionally, we have thought that if you replace a higher calorie meal with a lower calorie shake, that caloric deficit will produce weight loss — and for some, it can,” she explains. “For this reason, it may be one strategy that a health professional uses to support her client in weight loss.”

However, she says, there are a lot of assumptions that have to be made in order for shakes to work, including that the user will not have increased hunger from drinking a shake as opposed to eating a whole-foods meal and overcompensate by eating more later on.

“Drinks tend to be less satiating, and if they are high in sugar as well, the resultant blood sugar spike and low can lead to increased appetite that makes caloric restriction really uncomfortable,” Nielsen explains. “In addition, they do not teach people how to select and prepare meals that will help them to lose weight and keep it off long term, increasing the risk for a weight rebound when the user decides they want to eat real food again.”

And while many of the shakes are fortified with vitamins and minerals, most are hyper-processed, high in sugar or artificial sweeteners and don’t come close to the nutrition you would receive in a whole-foods diet, Nielsen says.

However, she says, many people are already not eating enough beneficial plant foods like fruits and vegetables, so losing even one meal a day can set a person up for nutritional deficits.

“Weight-loss shakes would never be my first choice if people feel that they need to lose weight to support their health and wellness goals,” Nielsen says. “Ideally, weight loss should be gradual through a shift in lifestyle that can be maintained for life so someone does not spend the rest of their life on and off diets, gaining and losing weight.”